Standard build.gradle configurations for a gradle based android app, with build flavours

build_buildtypes.gradle

 buildTypes {
 	debug {
            minifyEnabled false
            applicationIdSuffix '.debug'
            versionNameSuffix '-debug'
        }
        release {
            signingConfig signingConfigs.release
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

build_flavours.gradle

productFlavors{
        alpha {
            applicationId "com.yourcompany.appname.alpha"
            versionName "0.1-alpha"
        }
        beta {
            applicationId "com.yourcompany.appnam.beta"
            versionName "0.1-beta"

        }
        gamma {
            applicationId "com.yourcompany.appnam.gamma"
            versionName "0.1-gamma"

        }
    }

build_signing.gradle

signingConfigs {
        release {
            try {
                keyAlias KEYSTORE_ALIAS
                keyPassword KEY_PASSWORD
                storeFile file(KEYSTORE_FILEPATH)
                storePassword KEYSTORE_PASSWORD
            }
            catch (ex) {
                throw new InvalidUserDataException("You should define KEYSTORE_ALIAS, KEYSTORE_FILEPATH, KEYSTORE_PASSWORD and KEY_PASSWORD in gradle.properties.")
            }
        }
    }

gradle.properties

KEYSTORE_ALIAS=<keystore_alias>
KEYSTORE_PASSWORD=<keystore_password>
KEY_PASSWORD=<key_password>
KEYSTORE_FILEPATH=/path/to/your/keystore.jks